Tabletop Construction Problem

Gluing sawn lumber to plywood for a table top is asking for trouble. April 18, 2010

Question
I have a dining room table top approximately 4' wide with 10' long breadboard ends and four sides. Iím thinking of random widths 4/4 oak joined and glue jointed together then dressed to 3/4. I will glue and assemble boards and then glue to a piece of 3/4 plywood. After assembly sets up I will cut out a 2' section in the middle for leaf. Am I creating a movement problem? Any other thoughts?

Forum Responses
(Furniture Making Forum)
From contributor G:
This could be a big problem. Leave out the plywood.



From contributor C:
I second leaving out the plywood. Your solids will expand and contract. You cannot stop this, so don't glue plywood to it. What will hold your top? You must allow for expansion and contraction with your frame as well.


From contributor R:
The plywood will be a huge issue. It wonít stay flat for a week. Why not use 8/4 for the edges and the breadboards? Or use some nice oak veneer plywood instead of the solid top.


From the original questioner:
I forgot to tell you guys about the controlled temperature here. The risk just isnít worth it. Iím using a 6/4 breadboard all around.

What would be the best finish on this top? I plan to do top and bottom but want to help with the stabilization issue relevant to moisture.



From contributor T:
If you're using oak, you might consider rift or quartersawn. The movement will be minimized. Remember, even in a controlled environment there will be some movement. While I have heard differing opinions lately about finishing the top and underneath, I would still finish all surfaces with the same number of coats. As far as what finish to use - it depends on your capability and/or equipment. Also what look you are trying to achieve will help you determine the method and materials.


From the original questioner:
I just want a satin finish of some sort but something that will take punishment and seal the unit off from climate changes as best as possible.


From contributor G:
Regular polyurethane is a very tough finish. It's drawback is its slow drying time. If you used a 2K poly that would be very tough and then down the line from that is conversion varnish, pre cat lacquer, nitrocellulose lacquer. The tougher the finish, the harder it is to repair. Nitro is very easily repaired but is not very tough.